1. Field of the Invention
The present invention relates to wireless communication and, more particularly, to a method and apparatus for performing measurement in a wireless communication system.
2. Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) is an improved version of a universal mobile telecommunication system (UMTS) and is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) that is an evolution of the 3GPP LTE.
Techniques introduced to a 3GPP LTE-A includes carrier aggregation, a relay, and the like. The 3GPP LTE system is a single carrier system supporting only a single band width (i.e., a single component carrier) among 1.4, 3, 5, 10, 15, 20} MHz. However, LTE-A adopts multi-carrier using carrier aggregation. A component carrier is defined by a center frequency and a bandwidth. A multi-carrier system uses a plurality of component carriers having a band width smaller than the overall band width.
A terminal (or a user equipment (UE)) continuously performs measurement in order to maintain quality of a wireless link with a serving cell from which the UE is provided with a service. A cell or a frequency to be measured is called an object to be measured (or a measurement object), and a reporting configuration causing a report of a measurement result is independently associated to each management object. A UE performs measurement on management objects, and when a reporting configuration is satisfied, the UE reports measurement results to a base station.
In an existing measurement configuration structure, a reporting configuration may be associated with only one management object. However, as the multiple carriers have been introduced, there may be a plurality of serving cells, but how a plurality of serving cells are to be measured is yet to be presented.